1. Field of the Invention
The present invention relates to a meter register having an encoder, e.g., a visible light or infrared encoder, for measuring material flow, e.g., flow volume per unit time, and flow direction of water; to a method of adjusting the measured flow volume signal to more closely represent the actual flow volume per unit time flowing through the meter; and to an improved, mechanically-driven odometer.
2. Description of Related Art
One technique to determine utility consumption is to visually read the utility meters. The meters, such as water meters, include an odometer that indicates the amount of water consumed. The odometer is read periodically and the difference between the present and the prior reading determines the amount of water used. This procedure of individually and visually reading water meters is time consuming, labor intensive, and expensive. To overcome this drawback, remote reading systems were developed.
One such system is described in PCT Publication No. WO 02/073735 (hereinafter also referred to as “WO 02/073735”) to Winter and titled “Meter Register”. WO 02/073735 discloses a sealed meter register having a magnetic follower coupled to a gear. The gear includes a magnet that co-acts with one or more reed switch sensors. The reed switch sensors are coupled to a circuit board that determines the volume that flows through the meter by counting the number of pulses generated by the magnet co-acting with the reed switches. Then, the register circuitry forwards a signal that causes a radio wave to be transmitted or emitted by the meter register and picked up by a transmitter external of the meter register.
Although the meter register of WO 02/073735 is acceptable, there are limitations. More particularly, the use of reed switches and magnets on a wheel are rather expensive and, due to their mechanical nature, can fail in the field. The limitations of the meter register of WO 02/073735 are overcome by the encoder disclosed in application Ser. No. 10/864,312. In general, the encoder of application Ser. No. 10/864,312 has three electromagnetic wave emitters, e.g., infrared emitters, to measure water flow and direction of water flow through the meter. Two of the three spaced emitters are energized at predetermined time intervals to direct infrared rays toward a rotating detector wheel having a reflective surface portion. The reflective surface portion of the detecting wheel reflects the infrared rays incident thereon toward a sensor. A microprocessor connected to the sensor acts on signals from the sensor to determine material flow.
A powering arrangement for rotating the detector wheel includes a magnetic drive arrangement driving a gear train drive to rotate a gear mounted on a shaft of the detector wheel. A limitation of the encoder of application Ser. No. 10/864,312 is the expense of the gears.
As can be appreciated by those skilled in the art, it would be advantageous to provide a meter register that reduces the number of gears, or eliminates the gears, in the power arrangement.
Application Ser. No. 10/864,308 discusses the performance curve for meter registers made by various manufacturers. Of particular interest in the discussion is the accuracy of the measuring systems of the meter registers with respect to flow rate per unit time, e.g. but not limiting to the invention, flow volume of water per minute. In general, within a narrow range at low flow rates the measured volume was lower, and in a narrow range of higher flow rates the measured volume was higher than the actual volume of water flowing through the meter.
As can be appreciated, it would be advantageous to (1) provide a meter register that reduces the number of gears, or eliminates the gears, in the power arrangement and (2) provide a technique to measure flow rate per unit time that has minimal, if any, difference between the measured flow volume and the actual flow volume.